Being one tissue in the mammalian body that regenerates in postfetal life, bone is a promising tissue for research on morphogenetic matrix for osteogenetic gene expression. The proposed research deals with the following hypothetical constituents: the bone morphogenetic property (BMP), and insoluble polypeptide incorporated within the structure of collagenous matrices of dentin bone, and other calcified tissues; neutral proteinase (BMPase), geographically in close association with, but separable from BMP; BMPase-inhibitor, a soluble non-collagenous protein surrouding BMPase; and BMP-inhibitor, a high molecular weight soluble protein in juxtaposition to BMP. The investigative procedures are designed to separate and purify BMP by: (A) digestion of dentin and bone matrix gelatins with collagenase; (B) chemical extraction of dentin and bone with solvents for non-collagenous proteins; (C) thin layer ultrafiltration of osteosarcoma cell culture media. The methods include: filtration of tissue digests or extract on gel columns at different levels of pH; chromatography on ion-exchangers; paper or column electrophoresis. The morphogenetic constituents are demonstrable and bioassayed in implants of: (A) specific fractions of matrix in muscle in rats; (B) isolated substances in chemically-defined culture media in systems consisting of mesenchymal cell outgrowth of muscle into substrate prepared from denatured bone matrix; (C) isolated proteins implanted in double and triple walled millipore chambers in muscle and subcutaneous pouches in rabbits, rats, and mice pouches.